Today we are doing activity 21 found in the online book. Watch the video at the bottom of the blog first to see what we did in class.

Go to the online book and read the activity on page B-42 found in the Rocks and Minerals unit,
 
Student book:
1. Click on the link: http://lab-aids.com/
2. Click on the student link at the top of the website.
3. Enter the username and password.
USERNAME:  purdue7   /   PASSWORD:  science7

We are answering the questions found at the end of the activity on page B-44, 1-5.

1.    a. Was the thickness of the rock layers always the same?
       b. Which rock layer- A (on the bottom) or B (on the top) – formed first?
2.     Look again at the photo on page B-42 showing rock layers at the Grand Canyon. Which layer (the highest or lowest) is most likely to be the oldest? How do you know?
3.     Look at the diagram of rock layers at left. Imagine digging through the rock layers show in the diagram. As you dig, you find fossils! The S marks the pale where you find a snake fossil. The F marks the place where you find a fish fossil.
a. Which fossil –snake or fish- is most likely to be older? Explain how you came to this conclusion.

b. In a nearby area, coal has been found in a rock layer that is younger than the rocks containing  fish fossils. Knowing this, in which rock layer would you first look for coal? Explain.
4.    Do you think placing chips in a graduated cylinder was a good model of how rock layers form? Describe the strength and weaknesses of this model.
5.    Sometimes very old rocks are found on the earth’s surface. How do you think this may have happened?